Sewing-machine driving-shaft.



I. P. WEIS.

SEWING MACHINE DRIVING SHAFT.

APPLICATION FILED JUNE I5. I9I6.

Patented Apr. 15, 1919,

2 SHEETS-SHEET l.

IJldllIln IIIIIIIIIIIIIIIIIIIII l LLIPI IIxIII III.

I/I/TNESS 6mm Tem@ /VI/E/I/TR By W ATTORNEY J. P. WEIS.

SEWING MACHINE DRIVING SHAFT.

APPLICATION FILEDIUNE15.\9I6.

1,300,531 Patented Apr. 15,1919.'

2 SHEETS-SHEET 2 Arme/v' JOHN I. WEIS, OF NYACK, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 METRO- POLITAN SEWING MACHINE CORPORATION, OF DOVER, DELAWARE, A CORPORATION 0F DELAWARE.

Specication of Letters Patent. y

SEWING-MACHINE DRIVING-SHAFT.

lPatented Apr. 15, 1919.

Application mea :une i5, 191e. serial No. 10332:).

To all rwhom it may concern Beit known that I, JOHN zen of the United States, residing at Nyack, in the county of Rockland and State of New York, liave invented certain new and useful Improvements in Sewing-Machine Driving-v facture of machines; capable of high speed for either light `or heavy work and which will also permit various attachments or mechanisms to be operated from either a top orbottom shaft of the machine.

In order to operate such mechanisms or attachments it is desirable that the top and bottom rotary shafts have a positive drive from one to the other and these'rotary shafts must be properly balanced so that the machine will be free from vibration while operating at high speed.

In machines heretofore used with rotary top and bottom shafts the driving means connecting one shaft with the other was usually in the form of a belt, which has proven faulty, .even though the' bottom shaft was only used merely to drive the looper or bottom stitching mechanism. In other machines one or two connecting rods transmitted the motion from one shaftto the other, with the result that there wasl considerable lost motion at certain periods gear connections.

lIn' the present, 'mprovement all these disadvantages are done away with by the provision of a durable multiple top and bottom crankshaft having connections which will permit of their operation at' the highest speed without vibration, noise or lostmotion and one of the objects of the invention is to produce these shafts commercially at low cost, and the presentimprovement has been obtained only after considerable expenseand experimentation.-

These improved rotary shafts as arranged P. Wars, a citi-` for use in a sewing machine are provided with cranks and crank disks intermediate the ends of the shaft, thus leaving each end of the shaft free for driving connections,

.as for instance means for operating the needle lbar from the top shaft on one end and -for the hand wheel at the other end or top feeds or ruliing devices' may be driven therefrom, while the bottom feed mechanism is operated from one end of the 4bottom shaft and the belt wheel connections at the other' end thereof.

In the drawings accompanying and forming a part of tliisspecification, Figure 1 is a front view of the improvement, the sewing machine frame being shown in dotted lines, illustrating the bottom shaft provided with feed driving means at one end and a .belt wheel at the other, the top shaft with itsI vthe various parts ready to be assembled to form the shaft shown in Fig. 2. Fig. 4

' shows details of the crank pinr and Fig. 5 is a detail view of the crank shaft connection and .cap therefor. y

Similar lcharacters of'reference indicate corresponding parts in the several figures of the drawings. y

In the drawings the sewing machine frame 1 has suitable bearings 2 and 4 for the bottom rotary shaft 3. The end of this shaft carries a belt wheel 6 shown in section for rotatingtli-is bottom shaft. T-liis wheel and its belt operatewithin a housing 7 to protect the operator andthe work-from the wheel and its belt. The top rotary shaft 8 o erates in bearings 9 and 11 and is provided with a hand wheel 12. B having the hand wlieelfseparate from the elt wheel a material advantage is obtained because the hand wheel is grasped many times a day in` operating the machineand in this improvenient the belt does.`not interfere in any way. A needle bar 13 is operated b v the pitman 14 from the crank disk 15 secured tothe end of the top shaft 8.

As thescrank portions of the top and bot.- toni shafts are identical, a description of one will suffice for both. Shaft or shaft pory tion 3 for instance is drilled as at 16 to receive a stem 17 of the feed driving means. This stem is drilled and tapped as at 18 to receive a screw 19, the end of which screw impinges against one wall ofthe hole 16, while the head 21 acts as a key in the hole 22'of the shaft 3. Grooves 23 are provided for positively positioning the eccentric for operating the bottom stitch and feeding mechanism. The shaft 3 is reduced as at 24 and is knurled or otherwise roughened as at 25,'see Fig. 3. Four disks 26,26', 26, 26 are provided of equal thickness and diameter. One as 26 is drilled centrally as at 27 to receive the end 24 of the shaft 3, which is pressed therein up to the shoulder 28 of the shaft 3. The knurled or rough-l ened surface of the shaft end prevents the disk from turning on the shaft. A hole 29 is also provided in the disk 26 to receive the end 30 of the crank pin 31, while the opposite end 32 of the pin is forced into the hole 33 of the disk 26. drilled olf center of the disk to correspond with the hole 29. The distance that these crank pin holes are located from the center may vary to suit the conditions under which the shafts are used, but each crank pin of each shaft must be necessarily the same distance from the center in order to operate properly. The disk 26 is also drilled asv at 35 to receive the end 36 of a crank pin 37, while the end 38 is forced into the hole 39 of the disk 26". 26l receives the end 42 of the crank pin 43, while the-end 44 of this pin is forced into a hole 45 of the disk 26.- This last disk 26 is drilled centrally as at 47 to receive the end 48 ofthe shaft5. The reduced ends of the crank pins and shafts respectively are usually knurled or roughened to insure a tight positive driving-fit inreach o f the respective holes. The crank pins when assembled in the disks are located or spaced 120 'legrees from one another. In order that these shafts may be used at high speed, it is practically necessary to have Y them hardened. In the hardening process integral shafts of the length required become distorted or warped and before they can be assembled they must be straightened, but by making them in themanner shown much better results are obtained in manyl ways.

In assembling a shaft made in the manner described suitable jigs and fixtures are provided to facilitate the Work. According to one way of assembling the shaft the shaft 3 is placed in a jig and the reduced end 24 is forced into the hole 27 of its disk. Next the end 30 of the pin 37 is forced into the hole 29, then the opposite end 32 of this pin is forced into the hole 33 of the disk 26 and next the end 36 of pin 37 is forced into the hole 35. Then the end' 38 of this pin 37 is forced infto the hole This hole 33 is also A hole 41 in thedisk 39 of disk 26, then the end 42 of pin 43 is forced into the .hole 41 and the end 44 into the hole 45 of disk 26". Then the end 48 of shaft portion 5 is forced into the hole 47 of the disk 26 thus completing the assembling of the shaft. It is found in practice however, that the preferable Way of assembling the shaft is to first press the two center disks together on its connecting stud or pin and then thereafter assemble each end disk in sequence and then the short shaft 5 into its disk andv then the longer shaft 3 into its disk, the pressure exerted in assembling the several parts being so great that they are united in suchV an efficient manner that th/ey are permanently held together, and this without the necessity of any separate fastening pins, nuts or bolts. Then the shaft is ground and to facilitate the grinding operation, each crank pin is provided with a reduced portion 49, see Fig. 4, leaving the crank portion 50 full diameter, so that the grinding wheel can enter between the disks as at 51 to do this work without leaving a fillet or running close to the disks, which would interfere with the connections. The shaft connections or connecting rods 52 vare preferably made tubular, having the end bearings 52 andy 53 secured thereto. The cap 54 is likewise drilled at 55 to receive a wick 56 to conduct the lubricant from one shaft down through the tube to the other.

' By reason of the locaotionof the crank pins at 120 degrees from one another, the length of each connection 52, that is to say, from the center lines 57, is exactly the same.

I t has been demonstrated that with there is practically no strain on the screws, which hold the caps 54 in place so' that the machine will actually operate without the caps when' the top part of the sewing machine frame is placed upon the base and secured' thereto in the usual manner. The machine may be operated indefinitely without injury to the operating mechanism thereof, -therefore the location of themultiple cranks is important and it will be seen by viewing Fig. 1 that the shaft portion 5 operates in its bearing close to the disk 26 while the shaft 3 operates in its bearing l close to the disk 26, while the upper shaft portion 10 operates in a similar bearing close to a similar disk. The shafts are well supported to prevent springing thereof,

which overcomes the lengthwise strain of- I claim as inventiony.- A apertures, and wrist pins secured and held 1. A crank shaft comprlslng two spaced in said apertures by a tight fit whereby said and alined shafts, an end crank disk secured `on the adjacent end of each shaft, each of said disks having a wrist pin aperture, a plurality of intermediate crank disks having two wrist pin apertures, and wrist pins secured and held in fsaid apertures by a tight it.

2. A crank shaft comprising two spaced and alined shafts, an end crank disk secured on the adjacent end of each shaft by a tight fit, each of` said disks having a wrist pin aperture, a plurality of intermediate crank 'dis'ks having two wrist pin disks are connected solely by insertible wrist v pins located at spaced intervals relatively to each other around the crank disks, each of said wrist pinshaving reduced portions and also having together with the ends of the shafts reduced roughenedv portions of less' diameter than said first reduced portions.A y

Signed at Nyack, in the county of Rockland and Stateof New York, this 13th day of June,-1916.

' JOHN PQ wErs. 

